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Intel 8085
Introduced by Intel in 1977, the Intel 8085 is an 8-bit microprocessor that is binary-compatible with Intel 8080. It only requires a +5-volt power supply and has been used as a microcontroller.
1,493 Questions
Give the clock out frequency and state time T of 8085 when the crystal frequencies is 5MHz?
The clock out frequency of an 8085 is one half the crystal frequency. The period of one T cycle is the inverse of the clock frequency.
At a crystal frequency of 5MHz, the clock is 2.5MHz, and T is 400 ns.
An interrupt is a signal from a device attached to a computer or from a program within the computer that causes the CPU to stop executing the current program and figure out what to do next. It enable input/output device communicate or get the attention of the processor, and execute a program that need more attention.
According to word size how many instruction in 8085?
The 8085 is an 8 bit processor, so its word length is 8 bits.
What is instruction cycle with interrupts?
The instruction cycle is the basic operation cycle in a computer. This is what will take in data, process it and execute as required.
How many bits in 8085 microprocessor?
The 8085 is an 8-bit microprocessor.
Even though there are some 16-bit registers (BC, DE, HL, SP, PC), with some 16-bit operations that can be performed on them, and a 16-bit address bus, the accumulator (A), the arithmetic logic unit (ALU), and the data bus are 8-bits in size, making the 8085 an 8-bit computer.
What is the wait state in microprocessor?
The wait state, TWait, is a extra clock cycle added to the machine cycle to allow time for external hardware to respond. During this extra cycle, none of the address, data, or control pins change state. Wait state is entered if READY is false (LOW) on the rising edge of clock following ALE. READY is sampled each rising edge of clock thereafter and wait state will not be exited until READY is true (HIGH).
Explain different types of addressing mode?
Addressing modes are an aspect of the instruction set architecture in most central processing unit (CPU) designs. The various addressing modes that are defined in a given instruction set architecture define how machine language instructions in that architecture identify the operand (or operands) of each instruction. An addressing mode specifies how to calculate the effective memory address of an operand by using information held in registers and/or constants contained within a machine instruction or elsewhere.
Number of addressing modesDifferent computer architectures vary greatly as to the number of addressing modes they provide in hardware. There are some benefits to eliminating complex addressing modes and using only one or a few simpler addressing modes, even though it requires a few extra instructions, and perhaps an extra register.[1] It has proven[citation needed] much easier to design pipelined CPUs if the only addressing modes available are simple ones.Most RISC machines have only about five simple addressing modes, while CISC machines such as the DEC VAX supermini have over a dozen addressing modes, some of which are quite complicated. The IBMSystem/360 mainframe had only three addressing modes; a few more have been added for the System/390.
When there are only a few addressing modes, the particular addressing mode required is usually encoded within the instruction code (e.g. IBM System/390, most RISC). But when there are lots of addressing modes, a specific field is often set aside in the instruction to specify the addressing mode. The DEC VAX allowed multiple memory operands for almost all instructions, and so reserved the first few bits of each operand specifier to indicate the addressing mode for that particular operand. Keeping the addressing mode specifier bits separate from the opcode operation bits produces an orthogonal instruction set.
Even on a computer with many addressing modes, measurements of actual programs[citation needed] indicate that the simple addressing modes listed below account for some 90% or more of all addressing modes used. Since most such measurements are based on code generated from high-level languages by compilers, this reflects to some extent the limitations of the compilers being used
What is SIM and RIM instruction in microprocessor?
RIM stands for read interrupt mask and SIM stands for set interrupt mask.The SIM instruction is used to copy the contents of the accumulator into the interrupt mask.
The RIM instruction is used to interpret the RST interrupt positions.
What is an accumulator in microprocessor?
the accumulator is an 8-bit register then is part of the arithmetic/logic unit(ALU). this register is used to store to store 8-bit data and to perform arithmetic & logical operation. the result of an operation is stored in the accumulator. the accumulator is also identified as register A.
What is microprocessor and explain the parts of microprocessor using block diagram?
Block diagram
Working:
· CPU consists of three basic units: control unit, Arithmetic Logical Unit (ALU) and memory unit.
· Input is given through the input devices to CPU.
· Control unit controls communication within ALU and memory unit.
· Decides which circuit is to be activated.
· For reading instruction it uses Fetch-execute mechanism.
· Control unit gets instruction from memory.
· Control unit decides what to do of that instruction and transfers it to the ALU.
· ALU performs various arithmetic operations like addition, subtraction, multiplication, division and logical operations like AND, OR, NOT, NAND etc. on that instruction.
· Results of ALU are stored in the memory or resistor for its further operations.
· After completing the instruction, stored results are passed to the output devices.
· To synchronize all these operations CPU uses its own system clock.
Write a program to reverse the given string?
Use for loop
declare string array str[] and string variable
l= string length of string array
j=l
for i=0 to i=l/2 then
temp=str[i]
str[i]=str[j-1]
str[j-1]=temp
j=j-1
now print str array it will be reversed
What is the use of AC Flag in 8085?
The Auxiliary Carry (AC) flag in the 8085 indicates a carry out of the low order 4 bits of an operation, more specifically that the low order 4 bits are greater than 9 (10012). The AC flag can thus be used to facilitate decimal arithmetic.
What is the Difference between memory mapped IO and IO mapped IO?
In memory mapped I/O, a chunk of the CPU's address space is reserved for accessing I/O devices. In I/O mapped I/O, I/O devices are handled distinctly by the CPU and hence occupy a separate chunk of addresses predetermined by the CPU for I/O.
In case of Memory mapped I/O the same address BUS is used for accessing both Memory (RAM) and the Registers of I/O devices.
For I/O Mapped I/O, separate address BUS is used.
As Address space is generally larger for Memory than I/O registers, the length of I/O address is larger in case of Memory Mapped I/O.
For a system which uses I/O Mapped I/O, there is a requirement for a extra h/w Circuitry.
What is the fastest laptop processor readily available today?
EDIT:
After all that nonsence... AS of 2012 um... july 25
For the alienware m18x....
3rd Generation Intel® Core™ i7-3920XM (8MB Cache, up to 4.1GHz Overclocked*)
That would burn the whole battery in 1 hr so better have a desktop intead...
It would also cost 1.5k so better have the desktop....
Write 8085 program on selection sort algorithm?
LXI H,C000H //the length of the string is in C000 memory location//
MOV C,M
MVI E,00H
LOOP1: LXI H,C001H // string starts from C001 H //
MOV B,C
INX H
CMP M
JNC LOOP3
JZ LOOP3
MOV D,M
INR E // THIS IS TO CHECK WHETHER THE STRING IS ALREADY
SORTED OR NOT //
MOV M,A
DCX H
MOV M,D
INX H
LOOP3: DCR B
JNZ LOOP2
MOV A,E
SUI 00H
JZ LOOP4
DCR C
JNZ LOOP1
LOOP4: HLT
What are the effects of remedial instruction?
Remedial instruction aims to address learning gaps and improve academic skills for struggling students. It can lead to enhanced understanding of core concepts, increased confidence, and better overall academic performance. Additionally, targeted support can foster a positive learning environment, encouraging students to engage more actively with their education. However, the effectiveness of remedial instruction often depends on the quality of the program and the individual needs of the students.
How address decoding is done in Intel 8085 microprocessor?
Address decoding in the Intel 8085 microprocessor is done by latching the 8 bits of the AD0-AD7 bus during the ALE pulse, holding on the falling edge of ALE. After ALE, the latched results become A0-A7, and the AD0-AD7 bus becomes D0-D7.
What is the register of a microprocessor?
CPU's may have several types of registers and different manufacturers can throw in whatever they want. Typically there will be general purpose registers in varying numbers, depending on the manufacturer, program counter registers which contain the address of the next instruction to be executed, there may be stack pointer registers and whatever else the engineer(s) imagined.
It depends on the CPU used.
The 80x86 Processor can be broken into 4 categories...
- General Purpose Registers
- Special purpose Accessible Application registers
- Segement Registers
- Special Kernel Mode Registers
EAX, EBX, ECX, EDX, ESI, EBP.
AX, BX, CX, DX, SI, DI, BP, and SP
AL, AH, BL, BH, CL, CH, DL, and DH
- A processor often contains several kinds of registers, that can be classified according to their content or instructions that operate on them:
User-accessible Registers - The most common division of user-accessible registers is into data registers and address registers.
Data registers are used to hold numeric values such as integer and floating-point values. In some older and low end CPUs, a special data register, known as the accumulator, is used implicitly for many operations.
Address registers hold addresses and are used by instructions that indirectly access memory.
Some processors contain registers that may only be used to hold an address or only to hold numeric values (in some cases used as an index register whose value is added as an offset from some address); others allow registers to hold either kind of quantity. A wide variety of possible addressing modes, used to specify the effective address of an operand, exist.
A stack pointer, sometimes called a stack register, is the name given to a register that can be used by some instructions to maintain a stack (data structure).
Conditional registers hold truth values often used to determine whether some instruction should or should not be executed.
General purpose registers (GPRs) can store both data and addresses, i.e., they are combined Data/Address registers.
Floating point registers (FPRs) store floating point numbers in many architectures.
Constant registers hold read-only values such as zero, one, or pi.
CPU's may have several types of registers and different manufacturers can throw in whatever they want. Typically there will be general purpose registers in varying numbers, depending on the manufacturer, program counter registers which contain the address of the next instruction to be executed, there may be stack pointer registers and whatever else the engineer(s) imagined.
It depends on the CPU used.
The 80x86 Processor can be broken into 4 categories...
- General Purpose Registers
- Special purpose Accessible Application registers
- Segement Registers
- Special Kernel Mode Registers
EAX, EBX, ECX, EDX, ESI, EBP.
AX, BX, CX, DX, SI, DI, BP, and SP
AL, AH, BL, BH, CL, CH, DL, and DH
How many memory locations address bus can access?
A 10 bit address bus can address 210, or 1024 different locations.
What is the different between MOV and MVI in 8085?
In the 8085 microprocessor, the MOV instruction copies data between two registers, or between a register and memory. The MVI instruction differs only in that the source data is contained in the byte immediately following the opcode byte.
What determines whether a microprocessor is considered an 8-bit a 16-bit or a 32-bit device?
The number of bits a CPU uses to represent integer numbers (as opposed to floating point numbers or memory addresses) is often called "register width", "word size", "bit width", "data path width", or "integer precision".
This number is often considered one of the most important characteristics of a CPU.
Most CPUs are 8 bit CPUs. An 8 bit CPU -- i.e., a CPU where each register holds 8 bits -- typically has a 8 bit data bus and a 16 bit address bus.
One of the first 32 bit CPUs -- the MC68008 -- had registers that held 32 bits, a 20 bit address bus, and an 8 bit data bus.
Some popular 32 bit CPUs -- i.e., CPUs with registers that hold 32 bits -- had a 32 bit data bus and a 24 bit address bus.
Why microprocessor frequency is half of crystal frequency?
The crystal oscillator frequency in the Intel 8085 is divided by 2 because Intel designed it that way. Internal actions in the 8085 occur at various points in the cycle and, by dividing by 2, Intel could create 4 distinct points in the cycle where various edges could perform actions.
HOW IS SOFTWARE INTERRUPT INITIATED?
Interrupt signals initiated by programs are called software interrupts. A software interrupt is also called a trap or anexception.
A signal informing a program that an event has occurred. When a program receives an interrupt signal, it takes a specified action (which can be to ignore the signal). Interrupt signals can cause a program to suspend itself temporarily to service the interrupt.
Interrupt signals can come from a variety of sources. For example, every keystroke generates an interrupt signal. Interrupts can also be generated by other devices, such as a printer , to indicate that some event has occurred.
PCs support 256 types of software interrupts and 15 hardware interrupts. Each type of software interrupt is associated with an interrupt handler -- a routine that takes control when the interrupt occurs. For example, when you press a key on your keyboard, this triggers a specific interrupt handler. The complete list of interrupts and associated interrupt handlers is stored in a table called the interrupt vector table , which resides in the first 1 K of addressable memory.
How does 8086 determine wheather instruction is 8 bit or 16 bit?
based on the size of the data bus they determine whether it is a 8 bit or 16 bit . here in 8086 it has 16 bit data bus hence it is called as 16 bit microprocessor
